The present invention relates to new microcapsule formulations of agrochemically active compounds, to a process for their preparation, and to their use for applying agrochemically active compounds.
It is already known to stir agrochemically active compounds in the form of emulsifiable concentrates or wettable powders with water and to spray the plants with the resulting ready-to-use spray mixtures. The disadvantage of this method is that it is frequently very complicated to guarantee sufficient protection for the persons who apply these spray mixtures.
Furthermore, it has already been described that agrochemically active compounds can be applied in the form of aqueous microcapsule suspensions (cf. DE-A 3 016 189, DE-B 1 185 15, DE-B 1 248 016 and DE-A 2 734 577). However, it is inconvenient that such preparations often tend to agglomerate and that the active components which they contain are not always liberated in the desired quantity and over the intended prolonged period.
Finally, it can be seen from WO 98-29 360 that plant nutrients can be microencapsulated with the aid of isocyanate mixtures and polyols. However, the use of such isocyanate mixtures for microencapsulating agrochemically active compounds has not been disclosed as yet.
There have now been found new microcapsule formulations which are composed of
A) a particulate disperse phase of
a) a reaction product of
at least one diamine, polyamine, dialcohol, polyalcohol and/or aminoalcohol with
an isocyanate mixture obtained during the dimerization and/or trimerization of hexamehtylene-1,6-diisocyanate, of the formula
OCHxe2x80x94(CH2)6xe2x80x94NCOxe2x80x83xe2x80x83(I)
xe2x80x83xe2x80x83and/or during the reaction of hexamethylene-1,6-diisocyanate, of the formula (I), with water and/or carbon dioxide,
if appropriate in a mixture with toluylene diisocyanate,
b) at least one fungicidally active compound from the group of the amino derivatives, the morpholine derivatives or the azole derivatives and/or
at least one insecticidally active compound from the group of the phosphoric esters, the pyrethroids or the carbamates and/or
at least one herbicidal active compound from the group of the acetanilides and
c) if appropriate, additives, the particles of the disperse phase having a mean particle size of between 1 and 20 xcexcm and
B) a liquid aqueous phase.
Furthermore, it has been found that the microcapsule formulations according to the invention can be prepared by, mixing at least one fungicidally active compound from the group of the amino derivatives, the morpholine derivatives or the azole derivatives and/or
at least one insecticidally active compound from the group of the phosphoric esters, the pyrethroids or the carbamates and/or
at least one herbicidally active compound from the group of the acetanilides with
an isocyanate mixture which is obtained during the dimerization and/or trimerization of hexamethylene-1,6-diisocyanate, of the formula
OCHxe2x80x94(CH2)6xe2x80x94NCOxe2x80x83xe2x80x83(I),
xe2x80x83xe2x80x83and/or during the reaction of hexamethylene-1,6-diisocyanate, of the formula (I), with water and/or carbon dioxide,
if appropriate in a mixture with toluylene diisocyanate
and, if appropriate, with an organic solvent and, if appropriate, an emulsifier,
xcex2) then, in a second step, dispersing the resulting mixture in water, if appropriate as a mixture with additives, and,
xcex3) in a third step, adding at least one diamine, polyamine, dialcohol, polyalcohol and/or aminoalcohol, if appropriate as a mixture with water and then, if appropriate, adding further additives to the resulting dispersion.
Finally, it has been found that the microcapsule formulations according to the invention are highly suitable for applying the agrochemically active compounds which they comprise to plants and/or their environment.
It is considered as extremely surprising that the microcapsule formulations according to the invention are better suited to applying the agrochemically active compounds which they contain than the constitutionally most similar prior-art preparations.
What is particularly unexpected is that, amongst the large number of candidate isocyanates, it is especially the abovementioned isocyanate mixture, or mixture of isocyanate reaction products, which is particularly suitable for preparing microcapsule formulations which have the desired properties.
The microcapsule formulations according to the invention are distinguished by a series of advantages. Thus, they are capable of liberating the active components over a prolonged period in the particular amount required. Another advantage is that the plant tolerance of the active compounds which they contain is improved and, moreover, that the acute toxicity of the active components is also reduced, so that applying the microcapsule formulations is unproblematic for the operator, even without major safety precautions.
The microcapsule formulations according to the invention are characterized by the components contained in the dispersed phase and in the liquid phase.
The isocyanate mixture mentioned under (a) is obtained during the dimerization and/or trimerization of hexamethylene-1,6-diisocyanate and/or during the reaction of 1 mol of hexamethylene-1,6-diisocyanate and/or its dimers or trimers with 0.25 to 0.5 mol of water and/or 0.5 mol of carbon dioxide. Accordingly, these reaction products are uretidones, isocyanurates, biurets and/or oxadiazinetriones of hexamethylene-1,6-diisocyanate, of the formula (I).
Preferred mixtures are those which comprise isocyanates of the formulae 
Examples of such isocyanate mixtures which may be mentioned are:
Desmodur(copyright) N 3200
Desmodur(copyright) N 3300
Desmodur(copyright) N 3400
2H-1,3,5-oxadiazine-2,4,6-(3H,5H)-trione-3,5-bis-(6-isocyanato-hex-1-yl)
The isocyanate mixtures or reaction products of isocyanate mixtures mentioned under (a) have been disclosed (cf. WO 98-29 360). The same applies to toluylene diisocyanate, which is also mentioned under (a).
Suitable amines of the groups mentioned under (a) are, preferably, aliphatic and alicyclic primary and secondary diamines and polyamines. Examples which may be mentioned are 1,2-ethylenediamine, diethylenetriamine, triethylenetraamine, bis-(3-aminopropyl)-amine, bis-(2-methylaminoethyl)-methylamine, 1,4-diamino-cyclohexane, 3-amino-1-methyl-aminopropane, N-methyl-bis-(3-aminopropyl)-amine, 1,4-diamino-n-butane and 1,6-diamino-n-hexane.
These diamines and polyamines are known compounds of organic chemistry.
Suitable alcohols of the groups mentioned under (a) are, preferably, primary and secondary aliphatic dialcohols and polyalcohols. Examples which may be mentioned are: ethanediol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, glycerol and diethylene glycol.
These dialcohols and polyalcohols are also known.
An example which may be given of one of the aminoalcohols mentioned under (a) is triethanolamine. These aminoalcohols are also known.
The microcapsule formulations according to the invention may contain one or more of the agrochemically active compounds mentioned under (b).
Preferred fungicidally active compounds in this context are amino derivatives such as 8-(1,1-dimethylethyl)-N-ethyl-N-propyl-1,4-dioxaspiro[4,5]decane-2-methanamine (spiroxamine) and fenpropidin, and also morpholine derivatives such as aldimorph, dodemorph and fenpropimorph.
Other preferred fungicidally active compounds in the present context are triadimefon, triadimenol, bitertanol, dichlobutrazole, tebuconazole, propiconazole, difenoconazole, cyproconazole, flutriafol, hexaconazole, myclobutanil, penconazole, etaconazole, bromuconazole, epoxiconazole, fenbuconazole, tetraconazole, diniconazole, flusilazole, prochloraz, metconazole, ipconazole, fluquinconazole, triticonazole, triflumizole, imibenconazole, imazalil and 2-[2-(1-chloro-cyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-2,4-dihydro-[1,2,4]-triazole-3-thione.
Insecticidally active compounds of the groups mentioned under (b) which may preferably be mentioned are azinphos-methyl, azinphos-ethyl, bromophos A, chlorpyriphos, chlorpyriphos M, dichlorphos, edifenphos, fenamiphos, isofenphos, malathion, mesulfenphos, parathion A, parathion M, pirimiphos, profenofos, pyraclophos, tebupirimfos, betacyfluthrin, cyfluthrin, cypermethrin, transfluthrin und lambda-cyhalothrin, and furthermore aldicarb, aldoxycarb, aminocarb, bendiocarb, bufencarb, butacarb, butocarboxim, butoxycarboxim, 2-sec-butyl-phenyl methylcarbamate, carbanolate, carbaryl, carbofuran, cartap, decarbofuran, dimetilan, dioxacarb, ethiofencarb, fenethacarb, formetanate, formparanate, isoprocarb, methiocarb, methomyl, mexacarbate, nabam, nitrilacarb, oxamil, pirimicarb, promecarb, propoxur, thiofanox, thiocarboxim, thiram, trimethylphenyl methylcarbamate, 3,4-xylyl methylcarbamate and 3,5-xylyl methylcarbamate.
Herbicidally active compounds of the acetanilides mentioned under (b) which may preferably be mentioned are: alachlor, acetochlor, butachlor, metazachlor, metolachlor, pretilachlor and propachlor.
Suitable additives which the microcapsule formulations according to the invention may contain are organic solvents, emulsifiers, protective colloids, thickeners, preservatives, antifoams, antifreeze agents and neutralizers.
Suitable organic solvents are all customary organic solvents which, on the one hand, are sparingly miscible with water but, on the other hand, thoroughly dissolve the agrochemically active compounds employed. The following may be mentioned as being preferred: aliphatic and aromatic, optionally halogenated hydrocarbons such as toluene, xylene, Solvesso(copyright), tetrachloromethane, chloroform, methylene chloride and dichloroethane, furthermore esters such as ethyl acetate, and alkane carboxamides such as N,N-dimethyloctanecarboxamide and N,N-dimethyldecanecarboxamide.
Suitable emulsifiers are customary surfactants which are present in formulations of agrochemically active compounds. Examples which may be mentioned are ethoxylated nonylphenols, polyethylene glycol ethers of linear alcohols, reaction products of alkylphenols with ethylene oxide and/or propylene oxide, moreover fatty acid esters, alkylsulphonates, alkyl sulphates, aryl sulphates.
Suitable protective colloids (dispersants) are all substances which are usually employed for this purpose. The following may be mentioned as being preferred: natural and synthetic water-soluble polymers such as gelatin, starch and cellulose derivatives, in particular cellulose esters and cellulose ethers such as methylcellulose, furthermore polyvinyl alcohols, partially hydrolysed polyvinyl acetates, lignosulphonates, polyvinylpyrrolidones and polyacrylamides.
Thickeners which are suitable are all substances which can conventionally be employed for this purpose in plant treatment products. Preferred are Kelzan(copyright) (xanthan-based thixotropic thickener), silicas and attapulgite.
Suitable preservatives are all substances which are usually present in plant treatment products for this purpose. Examples which may be mentioned are Preventol(copyright) and Proxel(copyright).
Suitable antifoams are all substances which can conventionally be employed in plant treatment products for this purpose. Silane derivatives, such as polydimethylsiloxanes, and magnesium stearate may preferably be mentioned.
Suitable substances which may act an antifreeze agents are all substances which can conventionally be used in plant treatment productions for this purpose. Examples which may be mentioned are urea, glycerol and propylene glycol.
Suitable neutralizing agents are customary acids and bases. Phosphoric acid and aqueous ammonia solution may mentioned by way of example.
The particles of the disperse phase have a mean particle size which is generally between 1 and 20 xcexcm, preferably between 3 and 15 xcexcm.
The aqueous phase of the microcapsule formulations according to the invention is essentially composed of water. In addition, it may also comprise additives such as emulsifiers, protective colloids, preservatives, antifoams, antifreeze agents and neutralizing agents.
Preferred components are those which have already been mentioned as being preferred for these substances. In addition, the aqueous phase may also comprise small amounts of organic solvents and of the remaining constituents of the disperse phase.
The composition of the microcapsule formulations according to the invention can be varied within a certain range. Based on the entire formulation, the disperse phase generally amounts to between 30 and 70% by weight, preferably between 40 and 60% by weight. Within the disperse phase, too, the individual components may be varied within a certain range. Thus, the concentrations in the disperse phase are as follows:
reaction product of isocyanate mixture and diamine, polyamine, dialcohol, polyalcohol and/or aminoalcohol; generally between 1 and 2% by weight, preferably between 2 and 10% by weight.
agrochemically active substances: generally between 10 and 90% by weight, preferably between 20 and 80% by weight, and
additives: generally between 0 and 90% by weight, preferably between 10 and 80% by weight.
The microcapsule formulations according to the invention are prepared following the procedure for microencapsulation.
In general, a procedure is followed in which, as a first step of the process (stage xcex1), a solution of one or more agrochemically active compounds, isocyanate mixture, and, if appropriate, organic solvent and emulsifier is preferred. If the agrochemically active compound is a solid, it is generally employed in the form of a solution in an organic solvent. If the agrochemically active compound is liquid at room temperature, an organic solvent can be dispersed with. Preferred agrochemically active compounds, organic solvents and emulsifiers are those which have already been mentioned in connection with the description of the microcapsule formulations according to the invention as being preferred.
The quantities of the individual components are chosen in such a way that they are present, in the resulting disperse phase, in those concentrations which have already been mentioned as being preferred. The ratio of the isocyanate mixture mentioned under (a) to toluylene diisocyanate may be varied within a certain ratio. In general, between 0 and 10 parts by weight, preferably between 0 and 5 parts by weight, of toluylene diisocyanate are employed per part by weight of the isocyanate mixture mentioned under (a).
The solution prepared in stage xcex1 of the process according to the invention is dispersed in the second step of the process (stage xcex2) in water, if appropriate as a mixture with additives.
Suitable additives are protective colloids and emulsifiers. Preferably suitable are those substances which have already been mentioned in connection with the description of the microcapsule formulations according to the invention as being preferred protective colloids or emulsifiers.
To prepare the dispersions, all devices which are suitable for such purposes and which produce potent shearing forces may be employed. Examples which may be mentioned are rotor/stator mixers and jet dispersing machines.
The dispersion prepared in stage xcex2 of the process according to the invention is treated in the third step of the process (stage xcex3) while stirring first with at least one diamine, polyamine, dialcohol, polyalcohol and/or aminoalcohol. Here, the amine or alcohol components are expediently added in the form of an aqueous solutions. After the reaction which leads to capsule formation, additives may be added, if appropriate.
Suitable reactants are preferably all those diamines, polyamines, dialcohols, polyalcohols and aminoalcohols which have already been mentioned as being preferred in connection with the description of the microcapsule formulations according to the invention.
Suitable additives for carrying out stage xcex3 of the process according to the invention are thickeners, preservatives, antifoams, antifreeze agents and neutralizing agents. Those substances which have already been mentioned in connection with the description of the microcapsule formulations according to the invention as being preferred thickeners, preservatives, antifoams, antifreeze agents and neutralizing agents can preferably be used.
When carrying out the process according to the invention, the ratio of isocyanate to amine, or alcohol, components can be varied within a certain range. In general, 0.8 to 1.5 equivalents of amine, or alcohol, component are employed per mole of isocyanate. The quantities of isocyanate and amine, or alcohol, are preferably chosen in such a way that equimolar amounts of isocyanate groups and amino, or hydroxyl, groups are present.
When carrying out the process according to the invention, the reaction temperatures can be varied with a certain range. The process is generally carried out,
when carrying out the first step, at temperatures between 0xc2x0 C. and 40xc2x0 C., preferably between 2xc2x0 C. and 30xc2x0 C.,
when carrying out the second step, at temperatures between xe2x88x9210xc2x0 C. and +40xc2x0 C., preferably between 0xc2x0 C. and 80xc2x0 C. and
when carrying out the third step, at temperatures between 0xc2x0 C. and 80xc2x0 C., preferably between 10xc2x0 C. and 75xc2x0 C.
The process according to the invention is generally carried out under atmospheric pressure.
The microcapsule formulations according to the invention are outstandingly suited for applying the agrochemically active compounds which they contain to plants and/or their environment. They ensure liberation of the active components in the specific quantity desired over a prolonged period.
The microcapsule formulations according to invention can be employed in practice either as such or after previous dilution with water. They are applied by the customary methods, for example by pouring, spraying or atomizing.
The apparatus rate of the microcapsule formulations according to the invention can be varied within a substantial range. It depends on the agrochemically active compounds in question and on their content in the microcapsule formulations.
The invention is illustrated by the examples which follow.